So someone asked me recently to talk about the keys to being a great interviewer. I'm by no means an expert, but I'll try and provide some thoughts.
Here you go:

1. Do your homework. You would be amazed how many people show up to do an interview and have no clue about who they are interviewing, and just try to wing it. It shows. Believe me.

2. Ask the question behind the question. Get under the surface. Dig deeper. Not to uncover gossip or something that is not relevant, but because someone has probably already asked the question you are thinking about asking. So ask a better one.

3. Shutup. No one wants to hear your answer to the question, otherwise the tables would be turned. Your job is to pull great content out of the interviewee, not to give your opinion.

4. Create a conversation, not just a serve and volley. When appropriate, give the sense to your listeners that you are sitting in a living room having coffee and catching up. Creating conversation is different than just giving your opinion or an answer to your question. Conversations require context, which means you have to have 20 or 30 questions ready to go for an interview that would usually be around 10 questions.

5. Don't interrupt unless you need to, keep your hands off the table, and save your "ums" and "uh-huhs" and "oh-yeahs" for after you're done. For audio or video purposes, your agreeing by saying something just muddies the water. It seems like the thing to do in person- giving your interviewee verbal feedback, but just stick with non-verbal. Sounds better when you don't respond. And hitting or tapping the table is picked up by microphones- seems obvious, but everyone forgets.....

6. Listen. Seems obvious, but great interviewers actually listen to an answer being given, instead of preparing for the next question and not actually hearing what the person is saying. Listening creates great follow up questions. And creates trust with the interviewee.

7. Provide your questions beforehand. Send your questions to the person you are interviewing before the interview so they can prepare.

8. Make your interviewee the hero. Your job is to bring out the best in them. To uncover greatness. To reveal the good, true and beautiful. You also want to make them relatable, personable, and human. Which means you need to be those as well. If you're relatable, it will give them permission to be.